Polymeric materials have many advantages in both commercial and industrial applications compared to traditional materials such as glass. Typically they afford their user design freedom and advantageous properties such as decreased weight and reduced cost of production. An interesting area of application for the surface engineering of polymeric substrates is the design of ultrathin coatings for use in ‘everyday’ environments, such as easy-clean coatings on smart phones to mirrors and decorative (colourful) coatings in the automotive industry. For example, chrome finishes with custom colours and tints (often with a “brushed-metal” look) are becoming increasing desirable. Such coatings include tinted and deep dark chromes, as well as satin finishes. Furthermore, prolonged exposure to these ‘everyday’ environmental conditions requires such ultrathin coatings to possess a level of robustness against factors such as acidic or caustic environments, temperature variations from as low as −80° C. to highs of +80° C., variations in relative humidity, as well as abrasive conditions inflicted by everyday wear and tear.
Additionally, in almost all applications employing such coatings, there is a need for the coating to maintain its integrity over extended periods of operation under varying environmental conditions. That is, the coating should not significantly change reflectivity or colour within this time, nor should it delaminate or break away from the underlying substrate.
Further to the above characteristics of permanent and consistent integrity of the coatings, additional properties are desired. For example, in case such coatings are used as coatings for motor vehicle parts, it is desirable that the coatings also provide a certain degree of permeability to light from an natural or artificial light source. This may be suitable for example in case light from a side turn indicator should be visible even through the coating, which otherwise has a decorative effect in masking the light source.
Thus, there is a need for coatings for polymeric substrates that have an improved durability as well as provide characteristics that allow a certain degree of reflectivity and that can be substantially transparent so as to permit hidden lighting functionality if desired. These properties may be particularly useful for applications in motor vehicle components.
The above discussion of background is included to explain the context of the present invention. It is not to be taken as an admission that any of the material referred to was published, known or part of the common general knowledge at the priority date of any one of the claims.